/*
 * Licensed to the Apache Software Foundation (ASF) under one or more
 * contributor license agreements.  See the NOTICE file distributed with
 * this work for additional information regarding copyright ownership.
 * The ASF licenses this file to You under the Apache License, Version 2.0
 * (the "License"); you may not use this file except in compliance with
 * the License.  You may obtain a copy of the License at
 *
 *    http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.apache.linkis.server.utils;

import org.springframework.aop.framework.AdvisedSupport;
import org.springframework.aop.framework.AopProxy;
import org.springframework.aop.support.AopUtils;

import java.lang.reflect.Field;

public class AopTargetUtils {

  /**
   * Get target object(获取 目标对象)
   *
   * @param proxy 代理对象
   * @return
   * @throws Exception
   */
  public static Object getTarget(Object proxy) throws Exception {

    if (!AopUtils.isAopProxy(proxy)) {
      // Not a proxy object(不是代理对象)
      return proxy;
    }

    if (AopUtils.isJdkDynamicProxy(proxy)) {
      return getJdkDynamicProxyTargetObject(proxy);
    } else { // cglib
      return getCglibProxyTargetObject(proxy);
    }
  }

  private static Object getCglibProxyTargetObject(Object proxy) throws Exception {
    Field h = proxy.getClass().getDeclaredField("CGLIB$CALLBACK_0");
    h.setAccessible(true);
    Object dynamicAdvisedInterceptor = h.get(proxy);

    Field advised = dynamicAdvisedInterceptor.getClass().getDeclaredField("advised");
    advised.setAccessible(true);

    Object target =
        ((AdvisedSupport) advised.get(dynamicAdvisedInterceptor)).getTargetSource().getTarget();

    return target;
  }

  private static Object getJdkDynamicProxyTargetObject(Object proxy) throws Exception {
    Field h = proxy.getClass().getSuperclass().getDeclaredField("h");
    h.setAccessible(true);
    AopProxy aopProxy = (AopProxy) h.get(proxy);

    Field advised = aopProxy.getClass().getDeclaredField("advised");
    advised.setAccessible(true);

    Object target = ((AdvisedSupport) advised.get(aopProxy)).getTargetSource().getTarget();

    return target;
  }
}
